From: Joep Suijs <jsuijs@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Sat, 23 Jan 2021 23:50:30 -0800
Subject: Re: [PIC] PIC18F I2C Start/Stop condition detection
Thread-Topic: [PIC] PIC18F I2C Start/Stop condition detection
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Neil,

When looking at fig 26-17, it seems S remains high until stop is received.
The description mentions 'detected last', which -although not very specific
- might confirm that it remains high until a stop condition is detected.

Joep

Op zo 24 jan. 2021 om 06:59 schreef Neil <picdude3@narwani.org>:

> Hi all,
>
> I'm using I2C in slave mode on a PIC18F24Q10.  The incoming packets are
> like this...
> http://orlandorobotbuilders.com/stuff/WD-I2C-hold-packet-01.gif
>
> The PIC18F24Q10 datasheet is here...
>
> https://ww1.microchip.com/downloads/en/DeviceDoc/PIC18F24-25-Q10-Data-She=
et-40001945D.pdf
>
> The MSSP has a flag and interrupt for Start and Stop condition (S & P
> bits in SSPxSTAT) and I tried this code in the ISR to detect these...
>
>      if (SSP1STATbits.S =3D=3D 1)
>      {
>          TX1REG =3D 'S';
>          SSP1STATbits.S =3D 0;
>      }
>
>      if (SSP1STATbits.P =3D=3D 1)
>      {
>          TX1REG =3D 'P';
>          SSP1STATbits.P =3D 0;
>      }
>
> (I'm using EUSART1 for debugging to a serial terminal).
>
> But I'm getting the 'S' 6 times for each message, and It's repeating the
> 'P' several times, even after the message is over.  (The package is
> being sent once only).  Am I missing something obvious here?
> BTW, I've worked around this already, but just want to know now.
>
> Cheers,
> -Neil.
>
>
>
> --
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